The purpose of this project is to investigate the molecular structure of fibrous proteins, proteoglycans and the mineral in connective tissues. The structural information obtained will be correlated with function. Areas of present interest are 1) Structure of collagen and elastin. 13C magnetic resonance techniques are being used to study the structure and interactions in collagen and elastin fibers. 2) Proteoglycan structure. 13C magnetic resonance is also being used to study the molecular mobility of the polysaccharide and protein chains in the chick limb bud proteoglycan monomer. 3) Mineral structure is connective tissue. 31P magnetic resonance is being used to probe the structure of the phosphate moieties in mineralized tissue. 13C magnetic resonance is being used to study the extent and mechanism of hemoglobin S gelation in cell-free preparations and in erythrocytes. A magnetic resonance spectrometer has been assembled which obtains high resolution spectra of solids using high-power decoupling in either the cross-polarization or standard Fourier transform modes.